Data translating apparatus



Dec. 4, 1951 J. w. MAUCHLY EIAL DATA TRANSLATING APPARATUS Filed June 10, 1948 2 SHEETS-SHEET l 1 i8 22 I i +IOOV. 65 68 67 4J1- l I A/AW INVENTORS.

JOHN PRESPER ECMERT JR. JOHN W. MAUQKiLY e HCRNEY Dec. 4, 1951 J. W. MAUCHLY ETAL 2,577,141

DATA TRANSLATING APPARATUS Filed June 10, 1948 2 SHEETS-SHEET 2 V, IIB LTLI'LI'ULII I65 I66 am 130 INV EN TORSO JQHN PREfiPER ECKERT JR. JQHN W. MAUCHLY AT TGR NEY Patented Dec. 4, 1951 DATA TRAN SLATING APPARATUS John W. Mauchly, Philadelphia, and John Presper Eckert, Jr., Mount Airy, Pa., assignors to Eckert-Mauchly Computer Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application June 10, 1948, Serial No. 32,168

Claims.

This invention relates to data translating apparatus and more particularly to apparatus for translating the condition of a number of circuit controllers into a unique sequence of electrical impulses.

Recent years have witnessed the advent of the high speed digital computer in which electric impulses are utilized in controllin and performing various mathematical operations. The more advanced of these devices are capable of handling hundreds of thousands or even millions of digits per second. With respect to their manner of operation, such computers may be regarded as falling within two general classes; those handling all the digits comprising a number simultaneously in a number of circuits individually accepting and handling the separate digit places, and those using the same equipment for handling each of the various digits, but applying the digital information thereto in a time-spaced relationship. The two types of operation are conveniently designated parallel and sequential, respectively. It will be noted that it is necessary to separate in some manner the numeric information occurring in the difierent digit spaces of the numbers operated upon. In the parallel type of computer this separation is provided by circuit separation, while in the sequence type of computer the desired separation is secured by a spacing in time while using common circuits. Each of these computer classes presents problems peculiar thereto, but in each of them the tremendous speeds require special attention to the problem of reading in and reading out information. This grows out of the fact that such machines operate with a fixed time base, and that information cannot be manually supplied to such machines at a rate corresponding to their own normal rates of operation. The present invention concerns itself primarily with the problem of the sequence type computer.

It is a primary object of the invention to provide new and novel means for translating the condition of a number of circuit controllers into an impulse sequence.

It is a further object of the invention to provide new and novel means for rigidly relating the impulses comprising the sequence to the machine time-base.

Another object of the invention is to provide new and novel means of utilizing a delay path for translating the condition of a number of circuit controllers into a corresponding impulse sequence.

Other objects and advantages oi the invention will be in part described and in part be obvious when the following specification is read in conjunction with the drawings in which:

Figure 1 is a schematic diagram of a switch controlled data translating device incorporating the principles of the invention,

Figure 2 illustrates an alternative method of governing the operation of the signal transfer links,

Figure 3 illustrates a third method of governing the signal transfer link operation, and

Figure 4 schematically illustrates data controlled pulse generating apparatus having provisions for rigidly governing the pulse spacing with respect to a machine standard.

The device schematically illustrated in Figure l delivers a coded pulse sequence to the signal line l5 under the control of a plurality of circuit controlling devices here illustrated as switches Ill-I4, inclusive. Exciting pulses, utilized in the generation of the signal impulses delivered to the signal output line l5, arrive along the exciting pulse line l6 connected with the control grid [8 of a gate valve ll. As indicated, these exciting pulses are spaced by a time interval several times greater than their own width or duration. In addition to the grid IS, the valve I1 is also provided with a cathode l9 and anode 2| between which grid l8 and a second grid 20 are situated. The tube I1 is here employed in a manner wellknown to the art, the bias on the grids l8 and 20 being such that when either grid is negative, no current will pass between cathode and anode in response to potential variations on the other. The anode 2| of the gating tube I1 is connected with a source of positive potential through the load resistor 22 and also through a coupling capacitor 23 to the control grid 24 of the second valve 25. It should be here noted that the incoming pulses along the exciting impulse line l6 have a positive polarity which overcomes the normally present negative bias on control grid l8, and the cathode IQ of the gating valve I1 is returned to a potential of approximately volts positive. The grid 20 of the valve I1 is connected with an anode 32 of the tube 3| in the well-known flip-flop circuit 30. In addition to the anode 32, the flip-flop 3| is provided with an anode 33, cathodes 34 and 35, and the control grids 36 and 31, the even numbered elements being assembled as a first triode, while the odd numbered elements are assembled as a second triode. The anode 32 is connected with control grid 31 through a resistor 38 paralleled by a capacitor 50, while the anode 393 is connected with,

control grid 33 through a resistor 39 paralleled by a capacitor 4|. The anodes 32 and 33, respectively, are further'connected with a positive potential through resistors 42 and 43, while the cathodes 34 and 35 are returned to a relatively lower potential through the resistor 44. A resistor 45 connects the control gril 31 with the low potential end of the cathode resistor 4 and a second resistor 46 connects the control grid 36 with the low potential end of the cathode resistor 44. In addition, a. capacitor 41 is connected between the anode 32 and one end of the resistor 48, whose other terminal is connected with a point of relatively low potential. The capacitor end of the resistor 48 is also coupled through a switch 49 with a point of relatively high positive terminal. The switch 49 serves as the read-in switch and may be of the momentary type if desired.

The connection of the resistor 26 between th control grid 24 and cathode 21 of the discharge device 25 establishes substantially zero-bias operating conditions for this valve. Its anode 28 is connected with a source of approximately 100 volts positive potential through a load resistor 29 and may be coupled with a delay line 50 through the capacitor 5I. Its cathode 21 may be connected with a point of relatively low potential and is, in addition, linked with one side of each of the circuit-controllers Ill-I4, inclusive via the line 52. The delay line 50 may take any one of a number of well-known forms. It is illustrated as made up of a plurality of inductors 53-56, each mutually coupled with its neighboring inductor and the capacitors 51, 58, 59, 60, 6| connected individually between the inductor terminals and the common lead 9. A terminating impedance 62 is bridged between the output terminal of the last inductor and the common capacitor lead and linked with a source of potential sufiiciently negative to prevent current flow through the signal transfer tubes to be later described. The terminating impedance 62 is chosen in accordance with the well-known rules to minimize reflections.

A number of triodes ID-l4 have their control electrode individually connected with taps along the delay line 50. These taps may be so selected as to provide substantially equal delay intervals between the application of a narrow input pulse to successive control electrodes of triode devices Hi-l4. The anodes of the triodes ID-l4 are connected together and to a source of approximately 200 positive volts through a load resistor 63. They are further coupled to the signal output line I5 by the capacitor 64. In addition the cathode of triode I0 is connected with one side of the switch ID, the cathode of triode II is normally connected with switch II, the cathode of triode l2 with switch I2, the cathode of triode 13 with switch I3, and the cathode of triode 14 with switch I4. The other sides of the switches I0I4 are connected through line 52 with the cathode 21.

With the foregoing circuit details in mind, the operation of the apparatus may now be readily understood. Exciting pulses spaced by several pulse times arrive constantly along the exciting line I6 and are delivered to gating tube I'l. Normally, however, the even-numbered side of the flip-flop tube 3I is conducting, producing a relatively large voltage drop across the resistor 42. This resistor is returned to a source of approximately 100 volts positive and the cathode I9 of the gating valve I1 is connected to a point of similar potential, whence a substantial bias is impressed upon the grid 20, preventing electron flow between the cathode I9 and the anode 2i. At this time, therefore, no signals are delivered through the capacitor 23 to the discharge device 25. Let it be assumed that the switches Ill-I4 are in the positions shown and that it is desired to deliver a signal to the signal line I5 corresponding thereto. The switch 49 is closed and the resulting charging surge through the capacitor 41 produces a positive surge at the anode 32 and control grid 31. This establishes conduction through the odd-numbered side of the flip-flop tube 3|, whereupon the potential of anode 32 becomes much more positive, removing the blocking bias from the control grid 20 of the gating valve I1. Pulses corresponding to the exciting pulses on the line I6 are now delivered, with reversed polarity, through the coupling capacitor 23 to the inverter 25. The resulting current changes through the anode load resistor 29 develop signal pulses of the input polarity, which are then delivered to the input delay line so.

This pulse travels successively through the line sections until it reaches and is absorbed in the terminating impedance 62. It will be noted that the pulse duration is somewhat shorter than the nominal pulse period. The separation of the taps along the delay line 59 is such that the signal energy successively appearing at the taps is progressively delayed in increments approximately equal to the pulse period. This setup is designed to handle pulses spaced by five pulse periods, as illustrated in connection with the illustration of the signal on the exciting impulse line I6. The triodes ID-I l are normally nonconductive, and when the positive pulse from the inverter 25 arrives at the control grid of the triode 14, it gives rise to the output pulse in the representation of the pulses appearing on the signal output line I5. The impulse now travels on down the delay line 50, leaving its input and arriving at the junction between inductors 53 and 54 to excite the control grid of the triode l3, giving rise to another pulse of current through the load resistor 53 resulting in the transmission of a second pulse 56 on the signal line I5 in the second pulse period. Having left the junction between inductors 53 and 56, the impulse next passes to the junction between inductors 5 3 and 55 to excite the control grid of the coupling triode 12. In this case, however, the triode 12 is disabled by the opening of its cathode circuit at the switch I2, and no corresponding signal impulse is passed to the signal line I5. As the impulse arrives at the junction between inductors 55 and 56 a similar failure to transmit the pulse is observed, resulting in no pulses at either pulse period 3 or pulse period 3. Finally the signal pulse arrives at the terminated end of the delay line 50 to excite the control grid of thermionic valve I0, whose cathode circuit is complete permitting the development of a third pulse 61 on signal output line I5. In addition, the positive pulse appearing across the terminating impedance 62 is coupled to the anode 33 by the coupling capacitor 68 to drive this anode and control grid 36 positive. This transfers the flow of current from the odd-numbered side of flip-flop 3I back to the even-numbered side of flip-flop 3I biasing the control grid 20. of the gating tube I? strongly negative and interrupting the further flow of exciting impulses therethrough.

Therefore the data sequence set up on the register comprised by switches Ill, II, I2, I3 and I4 is transmitted in the form of electrical impulses to the signal output line I once for each closure of the switch 49. The signal transfer links connecting the taps on the delay line 50 with the signal output line I5 may, of course, be efiectively disabled by other means, examples of which are shown in Figures 2 and 3. In Figure 2 the cathodes of triodes and 1| are connected directly to a relatively low potential while the controlling switches I0 and II are connected between the taps on the delay line 50 and the control electrodes of their corresponding triodes. This arrangement, however, requires the addition of resistors and 16 connected between the control grids and a source of relatively negative potential to maintain the tubes 10 and H in normally nonconducting state. Still another variation is to be seen in Figure 3, where the control electrodes of triodes 10 and H are directly linked as before with the taps on the delay line 50, but the switches I0 and II are now situated in the connection between the triode anodes and the load resistor 63, the cathode being again returned to a point of relatively low potential. It may be noted that the register of switches in Figure l is situated out of the path of signal flow whereas the design of Figures 2 and 3 places the switches directly in the path of signal flow. This latter arrangement may be acceptable in a limited range of applications, but is somewhat inferior to the arrangement of Figure l in faithfully retaining the original input wave forms. It is indeed conceivable that the register of switches might have been connected directly between the taps on the delay line 50 and the signal output line I5 were it not for the fact that the bilateral flow of energy through the switches would give rise to multiple paths and reflections vitiating the fidelity of the output signal pulses.

As will by now have been observed the heaters associated with the thermionic cathodes of the discharge valves have been omitted to pre serve the simplicity of the illustration, as have the power supplies delivering the necessary potentials, since the details of this portion of the structure are well known to those skilled in the art and form no part of the present invention. For the same reason the showing of the coupling networks has been restricted to conventional resistance-capacity combinations, it being again understood that the usual broad-banding arrangements employing series and/or shunt-peaking may be employed where the frequencies are such as to indicate their desirability.

The more elaborate configuration of Figure 4 affords correspondingly improved performance characteristics. As before a gating valve I I7 has its control grid H8 connected with the exciting impulse line H6 and a control grid I connected with the flip-flop I30 here illustrated in block form. The cathode II9 of the gating valve I I1 may, as before, be connected with the terminal serving as the anode supply point for the anodes of the flip-flop I30. A load resistor I22 is connected between the positive supply point I3I and the anode I2I of the gating tube II1 while the anode I2I is also linked to the control grid I24 of the inverter tube I25 through the coupling capacitor I23.

The buffer inverter valve I25 is operated under substantially zero bias condition by virtue of the connection of a resistor I26 between the control grid I24 and cathode I21. Its anode I28 is connected with the positive supply point I34 through the load resistor I29. A suitable power supply delivers approximately 100 volts positive to the supply point I34. In addition, anode I28 is connected with the input of the delay line I50 through a coupling capacitor I5I. As in the previous illustration the delay line may be constituted of mutually coupled, series connected inductors I53, I54, I55 and I56 shunted by the capacitors I51I6I bridged between the inductor terminals and a common line I35. The delay line I50 is terminated by the connection of a suitable terminating impedance I62 between the inductor line and the common capacitor lead I35. One side of the terminating impedance I62 is connected to a suitable source of bias potential at I36 while its remaining terminal is connected with A side of the flip-flop I30 through the coupling capacitor I58 in addition to its connection with one lead of the delay element I39. A plurality of multiple grid valves I10-I14 are operatively associated with the delay line I50, the inner grid of valve I10 being connected with the terminated end of the delay line, the inner grid of valve I1I being connected with the junction between inductors I55 and I56, the inner grid of valve I12 being connected with the junction between inductors I54 and I55, while the inner grid of valve I13 is connected with the junction between inductors I53 and I54 and the inner grid of valve I14 is connected with the input to the delay line I50. In practice the presence of wiring and tube capacities may make possible the elimination of the capacitors I51 and I6I located at the input and output ends, respectively, of the delay line I50. The cathodes of the discharge devices I10-I14 may be connected together and to the supply point I31 which is maintained at a positive potential of approximately 100 volts. The anodes of the multiple grid valves I10-I14 may be connected together and thence to the supply point I3l through the common load resistor I63 while the output signal impulses are delivered to the signal line II5 through the coupling capacitor I64. The second grid of the discharge devices I10-I14 may be connected to the B side of the flip-flop register I40-I44. As shown in the diagram the A" side of the flip-flops I40-I44 is normally active and a positive potential therefore appears on the second grid of the multiple grid valves just referred to. The outermost grids of the discharge devices I10-I14 may be connected to a timing pulse line I68, through capacitors I16 and switches IIO, III, H2, H3 and H4, respectively. If the proper bias potential is present on the timing pulse line I68, it is permissible to omit the isolating capacitors I16. In either case however it may be necessary to provide grid resistors I15 having one end connected with the outer grid of its associated valve and the other end connected with the common line I11 connected with a suitable source of bias potential at I18. The parameters of the valves I10-I14 and the operating biases applied to the grid elements are so selected that an impulse is passed to the anode circuit only when all the grids are positive. This is a well-known form of coincidence gate.

The end of the delay element I39 remote from the terminating impedance I62 connected with the delay line I50 is linked through the lead I46 and switch I in common to the coupling capacitors I45 connected with the A side of the flip-flops I40-I44. The "B side of the flipflops I40I44may be connected through capacitors I19 to the respective control terminals I00-I84. By applying positive pulses from any .5 suitable source to the register input terminals 7 ISO-I04 it is possible to actuate the B" side of the flip-flops I40-I44 in any desired combination to control the nature of the impulses delivered to the signal line II as will be later described in detail.

The inner structure of flip-flops 30 and I40- I44 may be substantially identicalwith the detailed showing of such an element in Figure 1 and similar provisions are made for transferring conduction from the B side of flip-flop I30 to the "A side of this flip-flop. This takes the form of a capacitor I41 connected with one terminal of the resistor I48 whose other terminal is connected at I32 with a reference potential point. In addition, the capacitor terminal of the resistor I48 is connected through a normally open switch I49 with the point I33 normally maintained at a potential positive with respect to the terminal I32. '3

With the foregoing information. relative to Figure 4 in mind, its various modes of operation may be readily perceived. There are at least two obvious methods for use of this impulsegenerating apparatus and they will be discussed separately. Let it first be assumed that all circuit elements have the condition illustrated in the schematic diagram, that is, the B side of the flip-flop I30 is conducting current while the .A sides of fiipfiops comprising the register I40-I44 are conducting, switches I I0, I I3 and H4 are closed, switches III, H2 and I85 are open. Assume that it is now desired to deliver an impulse sequence to the signal line I5 corresponding to the switching register IIO-I I4, the switch I49 is closed momentarily, bringing the capacitor end of I48 to a positive potential and causing the passage of the charging pulse through capacitor I41 to transfer conduction from the B side of the flip-flop I30 to the A side of the flip-flop I30. This applies a positive potential to the grid I20 of the gating valve H1, and with the arrival of the next exciting impulse on the line I I6 a negatively poled pulse is delivered from its anode circuit through the coupling capacitor I23 to the control grid I24 of the buffer-inverter I25. This in turn gives rise to a positively poled pulse across the load resistor I29, which is delivered to the input of the delay line I50 to travel along the same until it is absorbed in the terminating impedance I62. Let it here be remembered that the exciting pulses are spaced in this example by five pulse periods and have a duration that is somewhat less than a pulse period. The positive pulse appearing on the inner grid of the multiple-grid valve I14, coupled with the already positive potential of the intermediate grid arising from the fact that B side of flipfiops I40-I44 is inactive, prepares the valve I14 for the passage of anode current as soon as the gating or timing pulse arrives on the line I68 and is transferred to the outer grid through switch H4 and capacitor I16. The input pulse to the delay line will not at this time appear at valves I10-I13 and hence the appearance of a timing pulse at their outer grids does not result in the flow of anode current through the load resistor I63. Thus only the multiple-grid valve I14 is active at this time. The beginning of the pulse, it will be seen, is controlled by the rise of the timing impulse on the gating pulse line I68, as is its termination. This is especially true as the impulse delivered by the delay line may have been broadened somewhat by its passage through additional circuit elements. After the lapse of one pulse period the delay line impulse is now at the 8 inner grid of the valve I13 and the arrival of the gating impulse on the line I68 again gives rise to an output impulse across the load resistor I62 and to the signal line H5 through the capacitor I64. The passage of the second pulse period brings the impulse to the inner grid of the valve I12. As revealed by inspection of Figure 4, the switch I I2 connecting the outer grid of this valve with the gating line is open and hence no impulse will be developed across load resistor I63. The same conditions obtain after the lapse of the third pulse time which brings the signal to the inner grid of valve I" which is similarly disabled because switch III is in the open position. The fourth pulse time brings the impulse to the inner grid of the valve I10 to prepare it for conduction in response to the gating impulse arriving from line I68 through closed switch H0 and capacitor I16. These operations give rise to the successive impulses through I65, I66 and I61, pictorially associated with the signal line II5. When the positive impulse on the delay line arrive at terminating impedance I62, it is also delivered to the A side of the flip-flop I30 through the capacitor I68 to transfer conduction back to the B side of the flip-flop I30, reducing the positive potential on the grid I20 of the gating tube II'ito a point preventing the further delivery of impulses in the anode circuit corresponding to the exciting impulses on the line H6. The delay line impulse is delivered as well to the input terminal of the delay element M9 at this time, but with the circuit conditions assumed this plays no further part in the operation of the apparatus.

However, when the switch IE5 is in the closed condition, the delay line impulse is delivered through the delay element I39 to the clearing line I46 to clear the flip-flop registers 50444. With the registers H6444 cleared, conduction is assumed by the B" side of the flip-flop effectively biasing related inputs of the gates I1I-I16 to close them. Thus, signal transfer gates I10-I14 are rendered nonresponsive to subsequent exciting impulses transmitted along the delay line I50 by the flip-flop registers lit-I66 until they are again set up with conduction on the A" side by the application of the necessary positive impulse to the register input terminals I-I84.

The operation of the manual register IIO-I I6 is easy of comprehension but obviously not capable of performing in a manner utilizing the full capacity of truly high-speed digital computers. Hence another type of relatively highspeed register comprising the flip-flops USU-I66 may be advantageously employed. If this type of use is contemplated for the pulse generating equipment, the switches IIOII4 are all closed or may be replaced by permanent connections. The normal condition of the flip-flop register i40-I44 for this type of operation is not that illustrated, but is one in which the 3" sides of the respective flip-flops conduct current. The flip-flop may be prepared or placed in this normal condition by impressing a positive pulse on the line I46 transferring conduction from the A" side to the B side thereof. The intermediate grids of all the. gating valves I10-I14 are now biased sufliciently negative with respect to their associated cathodes to effectively prevent the delivery of any signal impulses therefrom. The desired binary number or pulse combination is now set up by delivering positive pulses to the nals Ill-I84. Let it be assumed that positive pulses have been delivered through register impulse input terminals I80, I83 and I84 to transfer conduction back to the A sides of the flipfiops I40, I43 and I44. The intermediate grids of gating valves I10, I13 and I14 are therefore positive with respect to their associated cathodes and no longer act to permanently lock out these gating valves. When operating with the flip-flop register the switch I85, in the line I46, is left open if the register is not to be cleared after delivery of each pulse sequence and closed if it is desired to perform this clearing operation.

As before, the reading operation is initiated by closure of the switch I49 to pass a positive charging pulse through capacitor I41 to the B" side of the flip-flop I30 and effectively applying a positive potential to the grid I20 of the gating valve II1. Upon arrival of the next succeeding impulse through the exciting impulse line II6, a negatively poled pulse is developed across the anode load resistor I22 and delivered through the coupling capacitor I23 to the buffer-inverter I25, in whose output circuit a corresponding positively poled pulse appears, which is then delivered to the input of the delay line I50. The delay line is so proportioned that each section provides a delay substantially equal to one pulse period. The arrival of the delay line impulse at the gating valve I 14 drives its inner grid positive. The intermediate grid of this valve is already positive, hence with the arrival of a positive gating impulse along the line I68 and through the switch H4 and capacitor I16, the tube I14 draws anode current, generating the pluse I65 across load resistor I63, which is passed to the signal line I I through coupling capacitor I64. Because of the delay characteristics of the line I50, the delay pulse will not have yet arrived at the inner grids of gating valves I-I13 which, therefore, do not participate at this time. After the lapse of the first pulse period the delay line pulse is impressed on the inner grid of the gating valve I13 whose intermediate grid is also positive and it too delivers an anode current pulse upon the arrival of a positive gating impulse from the line I68 through switch H3 and coupling capacitor I16. As before, the delay line impulse will not have reached gating valves I10-H2 and will have already departed from the inner grid of gating valve I14 whereby these latter tubes are effectively removed from operation. The lapse of the second pulse period brings the delay line impulse to the gating valve I12.

It has earlier been specified; however, that the B side of the flip-flop is conducting and hence its intermediate grid is negative with respect to the cathode eifectively preventing the development of a signal pulse in the third space. The passage of the third pulse period brings the delay line impulse to the gating valve I1I whose inter mediate grid is similarly negative with respect to its cathode thus preventing the developing of a signal impulse in the fourth pulse space. The lapse of the fourth pulse brings the delay line impulse to the terminating impedance I62 and the inner grid of the gating valve I10 whose intermediate grid is positively biased, as the flipiiop I40 is conducting on the A side. This gives rise to the development of a pulse I61 in the fifth pulse period in response to the arrival of the positive gating impulse over the line I68 through the switch H0 and capacitor I16. The positive pulse appearing across the terminating impedance I62 is also delivered to the flip-flop I30 through the coupling capacitor I68 on its A side and it transfers conductance back to the B" side of the flip-flop. effectively biasing the grid I20 of the gating valve II1 strongly negative with respect to its associated cathode H9, preventing the further passage of exciting impulses through this tube. In addition the output pulse across the terminating impedance I62 passes through the delay element I39 and the closed switch I85, line I46 and the coupling capacitors I45 to the A sides of the flip-flops comprising theregister I40-I44. This clears the flip-flop register by transferring conduction to B sides of all the flip-flops, thereby placing such a bias on the intermediate grids of the gating valves I10-I14 as to prevent the further passage of impulses. The flip-flop register I40-I44 may again be set up in any manner by the application of the necessary positive impulses to the register input terminals I-I84. The delay provided in the delay element I39 is substantially equal to the duration of the gating pulses on the line I68 and its purpose is to prevent closing the gating valve I10 before the completion of transmission of a pulse therethrough. It is not necessary to delay the clearing of the flip-flops associated with the gates I1I-I14 since their function will have been previously performed. Therefore, it is possible to place the delay element I39 either in the line I46 or in the individual connection to the flip-flop I40. If it is desired to transmit the same number to the signal line repeatedly, the switch I in the clearing line I 46 is left open, and the reading switch I49 pressed as many times as it is desired that the register number be read out.

In the illustrated embodiment, a single tapped transmission line has been employed for the development of the spaced reading pulses. It will be obvious however, that if desired, individual delay lines characterized by different delay times might connect the output of the buffer-inverter with the respective gating valves I10-I14. Such a modification could also be employed in the apparatus of Figure 1. Furthermore, although a relatively elemental form of impulse generating apparatus for the initiating of the read-in apparatus has been shown, it is clear that any available source of suitable positive impulses may be employed for this purpose. In addition the choice of pulse polarity is one of convenience and pulses of a negative polarity might be used as satisfactorily as those of positive polarity, with minor modifications.

Hence, it is clear that there will be many modifications and variations not departing essentially from the principle of the invention obvious to those skilled in the art. One such modification would be the replacement of the electric discharge devices used as signal links in Figure 1 with switches operating in circuits with sufficiently high attenuation to reduce the effect of reflections and multipath signals on the line 50 to a tolerable level.

What is claimed is:

1. In impulse generating apparatus, a passive signal delay line characterized by a predetermined delay interval and provided with a plurality of connections along its length, a device delivering conditioning impulses to said delay line spaced in time by an amount at least equal to the delay interval of said signal delay line, and of duration less than said delay interval, an output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line and at least two input leads, said signal gates being conditioned to deliver an output signal by the presence of coinciding signals of selected polarity on said input leads, means connecting the first input lead of each of said signal transfer gates with a respective connection of said signal delay line, a plurality of data responsive registers characterized by a first state and a second state, each of the said registers in the first state conditioning the second input lead of a respective one of said gates, means for selecting the state of each of said data responsive registers, and a signal transfer gate disabling device conditioned by an impulse applied from said signal delay line to render said signal transfer gates nonresponsive to subsequent conditioning impulses.

2. In impulse generating apparatus, a passive signal delay line characterized by a predetermined delay interval and provided with a plurality of connections along its length, a device controlled to deliver a single conditioning impulse to said delay line having a duration less than the delay interval of said signal delay line, an output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line and at least two input leads, said signal gates being conditioned to deliver an output signal by the presence of coinciding signals of selected polarity on said input leads, means connecting the first input lead of each of said signal transfer gates with a respective connection of said signal delay line, a

plurality of data responsive registers characterized by a first state and a second state, each of the said registers in the first state conditioning the second input lead of a respective one of said gates. means for selecting the state of each of said data responsive registers, and a signal transfer gate disabling device excited by the conditioning impulse applied to the first input lead of one of said signal transfer gates to render said signal transfer gates nonresponsive to subsequent conditioning impulses.

3. In impulse generating apparatus, a passive signal delay line characterized by a predetermined delay interval and provided with a plurality of connections along its length,- a device delivering conditioning impulses to said delay line spaced in time by an amount at least eoual to the delay interval of said s gnal delay line and of duration less than said delay interval, an

output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line and at lea t two input leads, said si nal ates being conditioned to deliver an output signal by the presence of coinciding signals of selected polarity on said input leads, means connecting the first input lead of each of said signal transfer ga es with a respectlve connection of said si nal delay line, a plurality of data responsive re isters each having a setup state and a clear state. each of said registers in the setup state conditioning the second input lead of a respective one of said gates, means for selectively setting up said data responsive registers, and a reg ster clearing apparatus activated by an impulse applied from said si nal delay line to clear said data responsive registers.

4. In impulse generating apparatus. a passive signal delay line characterized by a predetermined delay interval and provided with a plurality of connections along its length, a device delivering conditioning impulses to said delay line spaced interval of said signal delay line and of duration less than said delay interval. an output signal line, a plurality of signal gating valves each having an output lead connected with said output signal line and at least two input leads, said signal gating valves being conditioned to deliver an output signal by the presence of coinciding signals of selected polarity on said input leads, means connecting the first input lead of each of said signal gating valves with a respective connection of said signal delay line, a plurality of flip-flop circuits each having a setup state and a clear state and provided with setup and clear input leads, each of the said circuits in the setup state conditioning the second input lead of a respective one of said signal gating valves, means connected with the setup input leads for selectively setting up said flip-flop circuits, and a signal delaying link connected between the first input lead of one of said signal gating valves and the clear input leads of said flip-flop circuits.

5. In impulse generating apparatus, a signal transfer gate having at least two input leads and an output lead, said signal gate being conditioned to deliver an output signal by-the presence of coinciding signals of selected polarity on said input leads, an exciting line delivering impulses spaced by a predetermined time period exciting the first input lead of said signal transfer gate,

-a signal responsive register having a setup state and a clear state and provided with setup and clear input leads, said register in the setup state conditioning the second input lead of said signal transfer gate, a s gnal line for delivering setup signals to the setup input lead of said signal responsive register, and a signal delay device characterized by a delay interval less than the period of impulses on said exciting line and embracing an input lead connected with the output lead of said signal transfer gate and an output lead connected with the clear input lead of said signal responsive register.

6. In impulse generating apparatus, a selector signal gate having at least two input leads and an output lead, said selector signal gate being conditioned to deliver an output signal by the presence of coinciding signals of selected polarity on said input leads, an exciting line delivering impulses spaced by a predetermined time period and having a predetermined duration exciting the first input lead of said signal transfer gate, a signal responsive register having a setup state and a clear state and provided with setup and clear input leads, said register in the setup state conditioning the second input lead of said signal transfer gate, a signal line for delivering setup signals to the setup input lead of said signal responsive register, a passive signal delay line characterized by a delay interval less than the time period of impulses on said exciting line but more than the duration of said impulses and provided with an input lead connected with the output lead of said selector signal gate an output lead connected with the clear input lead of said signal responsive register and a plurality of connections along its length, an output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line and at least two input leads, said signal gates being conditioned to deliver an output signal by the presence of coinciding signals of selected polarity on said input leads, means connecting the first input lead of each of said signal transfer gates with a respective connection of said signal in time by an amount at least equal to the delay (5 delay line, a plurality of data responsive registers characterized by a first state and a second state, each of the said registers in the first state conditioning the second input lead of a respective one of said gates, means for selecting the state of each of said data responsive registers, and a signal transfer gate disabling device conditioned by an impulse applied from said signal delay line to render said signal transfer gates nonresponsive to subsequent conditioning impulses.

7. In impulse generating apparatus, a passive signal delay line characterized by a predetermined delay interval and provided with a plurality of connections along its length, a gating pulse source delivering impulses having a period less than the delay interval of said delay line, a device governed by said gating pulse source delivering conditioning impulses to said delay line spaced in time by an amount at least equal to the delay interval of said signal delay line and of duration less than said interval, an output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line and at least two input leads, said signal gates having the property of delivering an output signal in the presence of coinciding impulses on said input leads, means connecting the first input lead of each of said signal transfer gates with a respective connection of said signal delay time, means selectively connecting the second input leads of said signal transfer gates with said gating pulse line,

and a signal transfer gate disabling apparatus conditioned by a pulse applied from said signal delay line to render said signal transfer gates noresponsive to subsequent coinciding input impulses.

8. In impulse generating apparatus, a passive signal delay line characterized by a predetermined delay interval and provided with a plurality of connections spaced along its length in substantially equal delay subintervals, a gating pulse source delivering impulses having a period substantially equal to a delay subinterval of said signal delay line, a device governed by said gating pulse source delivering conditioning impulses to said delay line spaced in time by an amount at least equal to the delay interval of said signal delay line and of duration not exceeding said subintervals, an output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line ard at least two input leads, said signal gates having the property of delivering an output signal in the presence of coinciding impulses on said input leads, means connecting the first input lead of each of said signal transfer gates with a respective connection of said signal delay line, means selectively connecting the second input leads of said signal transfer gates with said gating pulse line, and a signal transfer gate disabling apparatus conditioned by a pulse applied from said signal delay line to render said signal transfer gates nonresponsive to subsequent coinciding input impulses.

9. In an electric signalling network, a source of electric impulses spaced substantially equal predetermined periods of time, a transmission device characterized by a transmission delay embracing a plurality of said periods of time and provided with output connections spanning substantially an integral number of said periods of time, apparatus governed by said source of electric impulses supplying impulses spaced in time by an amount at least equal to said transmission delay to the input of said transmission device, a gating link having first and second input connections and responsive only in the presence of stimuli on both of said input connections, a connection between said source and said first gate input connections, a connection between one of the output connections of said transmission device and said second gate input connection, and a load device connected with the output of said gating link.

10. An impulse generating apparatus, a passive signal delay time characterized by a predetermined delay interval and provided with a plurality of connections along its length, a gating pulse source delivering impulses having a period less than the delay interval of said delay line, a device governed by said gating pulse source delivering conditioning impulses to said delay line spaced in time by an amount at least equal to the delay interval of said signal delay line and of duration less than said delay interval, an output signal line, a plurality of signal transfer gates each having an output lead connected with said output signal line and at least three input leads, said signal gates having the property of delivering an output signal in the presence of coinciding signals of selected polarity on said input leads, means connecting the first input lead of each of said signal transfer gates with a respective connection of said signal delay line, means connecting the second input leads of said signal transfer gates with said gating pulse line, a plurality of data responsive registers each having a setup state and a clear state, each of said registers in the setup state conditioning the third input lead of a respective one of said gates, means for selectively setting up said data responsive registers, and a register clearing apparatus activated by an impulse applied from said signal delay line to clear said data responsive registers.

JOHN W. MAUCHLY. 1 JOHN PRESPER ECKERT, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,199,634 Koch May 7, 1940 2,210,577 Fitch Aug. 6, 1940 2,403,561 Smith July 9, 1946 2,409,229 smith Oct. 15, 1946 2,418,521 Morton Apr. 8, 1947 2,456,825 Fitch et a1. Dec. 21, 1948 2,543,874 Shenk Mar. 6, 1951 

